Orson Scott Card wrote of Blade Runner, "It takes place in Los Angeles. No aliens at all. But it isn't the L.A. we know ... things have changed. Lots of things, moving through the background of the film, give us a powerful sense of being in a strange new place". The film depicts a world post ecocide, where warfare and capitalism have led to destruction of 'normal' ecological systems. The climate of the city is very different from today's. It is strongly implied that industrial pollution has adversely affected planet Earth's environment, i.e. global warming and global dimming. Real animals are rare in the Blade Runner world. In Philip K. Dick's 1968 novel, Do Androids Dream of Electric Sheep?, animal extinction and human depopulation of the planet were consequent to the radioactive fallout of a nuclear war; owls were the first species to become extinct. This ties in with Deckard's comment about Dr. Tyrell's artificial owl: "It must be expensive." (Wikipedia)
